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jerrylo 10-23-2004 10:37 PM

primer orange peel help
I am spraying 2k primer with a finishline hvlp gun with a 1.8 tip. I set the regulator at the compressor at 45 psi and the regulator at the gun at 20 psi with the trigger pulled. Trying to hold the gun at 6". I seem to be getting a lot of orange peel. When I block the primer so that all traces of peel are gone, it seems like I am sanding most of the primer off. Can anyone offer me any tips to get rid of it? Will a sealer hide some of the orange peel?

53fordguy 10-23-2004 11:28 PM

same problem
1 Attachment(s)
i have had the same problem on this little art panel im making after messing around a bit adding a small bit of extra thinner to your catalyst and your primer helps alot! heres my orange peel

Live To Paint 10-24-2004 12:20 AM

Increase the air pressure by 5-10 psi and turn your fluid down. This will cause better atomization. Resulting in less orange peel. Primer should be sanding complete smooth before sealer and further painting is applied.

troy-curt 10-24-2004 07:56 AM

When using a sealer, you should sand most of the primer off as it is just a filler and leveler. You don't want to much thickness under the paint. Try backing off to 8-10 inches.


sevt_chevelle 10-24-2004 11:02 AM

I dont know the finishline gun but Id be willing to bet that the pressure at the gun should be set somewhere around 40

julmer 10-24-2004 10:51 PM

I'm almost certain you air pressure is too low. The lowest I've seen for an HVLP gun is 23, more common is about 30 and a few guns require as much as 40 at the gun. I'd suggest 30 psi at the gun for a starting point.

jerrylo 10-25-2004 09:16 PM

Finishline is made by devilbiss. I got my original settings from the manual and it says the inlet pressure should be 23 psi and have an air flow of 13 scfm which will give you a cap pressure of 10 psi. I just bought a new ingersol 60 gal. 2 stage compressor so I know that air flow is not the problem, it is just me learning how to properly set it. The pressure did seem low to me, but this is my first time using a hvlp gun. I will sure try raising the pressure to get rid of the orange peel. I got most of it blocked off yesterday and I do not feel like doing that again. Do any of you measure the pressure at the aircap?

julmer 10-25-2004 09:48 PM

A test cap with a gauge is the official way to set the gun but, in the real world, you adjust it until it works best. Most people think a little higher pressure gives you a better job.

jerrylo 10-25-2004 10:02 PM

Appreciate the advise. I am going to set up a few test panels and spray them at higher pressure settings and see which one turns our the best. I am beginning to think that the spec. sheets are printed more for OSHA compliance than for user friendliness.

dh79 10-26-2004 01:37 AM

I use a finishline III gun and when I first got it I had a problem with orange peel. I've found that it likes more pressure. I usually do 23-25 inlet psi and it'll lay down smooth. It may be rated for hvlp at 23 psi, but I'm not convinced that's it's ideal pressure in the real world. Bump it up just a bit and see what happens. My 0.02.

Vintage Kolours 10-27-2004 04:19 AM

primer orange peel
A few suggestions that should get you spraying orange peel free
First off, 1.8 is kinda big, better word is it's huge. I'd suggest using a 1.5 tip.
Here's a few tips that work at my shop.
Set you wall regulator to 100psi, this should give you the cfm that your gun requires and with out the added pressure drop. Next set the micrometer at the gun to factory specs with the trigger fully pressed and fan wide open. Next your going to set your fluid needle's volume. Completely back out the volume adjustment screw until it comes completely off, then just start the screw back in so that there is now pressure on the needle's spring.
Next fully trigger the gun (of course with it disconnected from the air line and no material in the gun) and start turning the volume control screw until you feel pressure on the trigger. This is what you call a full trigger which most guns are designed to spray at.
Now for the test patter test. The rule of thumb is 8x8. 8 inch fan and 8 inch distance from what your painting. With the gun fully loaded with paint, and using the 8x8 rule, which at this time don't mess with the air setting that will be later, full trigger the gun and close it. This should be a quick movement. Now inspect your spay pattern. This spray pattern shows everything. runs, dry spray, everything if you know what to look for. The major cause of orange peel is to much material incorrect reducer/thinner, and air pressure.
Never get in a hurry, and never try to have complete hiding with one coat. Way to much material. We usually have complete hiding by 4 to 5 coat. Nice light coats is all you need. Now there is a difference between light and dry. The paint shouldn't feel or look like sandpaper If it does then drop your air pressure by 5psi and shoot again. If you experience runs, increase the air pressure by 5 psi. If it still runs then close the fluid needle in 1/16 of a turn increments. Most of the time you don't want to go under or over the factory specs more than 5 to 7psi.
Now with the reducer and thinner, follow the P sheet for the material that your using. Don't become a chemist, that is what you paid them for. Now once again there is an exception to every rule, Use the lowest possible temp range that you can get away with without causing runs. So if your shooting during the winter try a normal reducer instead of a fast reducer, but mix the stuff according to the P Sheet. And one more thing, don't expect to get a great performance from cheap materials.
Hope this helps out
Vintage Colours

jerrylo 10-28-2004 05:52 PM

Excellent post Corey. You explained a lot about the setting of a paint gun. I will try to follow what you said. This needs added to FAQ #4.

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